.\" RCSid $Id: genklemsamp.1,v 1.5 2012/06/14 22:42:21 greg Exp $
.TH GENKLEMSAMP 1 6/13/09 RADIANCE
.SH NAME
genklemsamp - generate ray samples over surfaces using Klems BSDF basis
.SH SYNOPSIS
.B genklemsamp
[
.B "\-c N"
][
.B "\-f{a|f|d}"
]
[
.B "view opts"
]
[
.B "geom.rad .."
]
.SH DESCRIPTION
.I Genklemsamp
generates ray origins and directions to sample planar surfaces
needed to determine incident radiances or daylight coefficients.
This command is typically used in conjunction with
.I rcontrib(1)
to analyze exterior daylight coefficients
for an annual simulation.
.PP
The view options are needed to specify (at minimum) the view direction,
which corresponds to the orientation of the surfaces, and the view up
vector, which corresponds to the azimuth=90-degree position on the Klems
sampling hemisphere.
The view fore clipping distance is also quite useful, as it provides
a means to pass through some thickness in a fenestration system before
samples are sent out.
Other view options such as the view type and aft
clipping distance are overridden or ignored.
.PP
If no Radiance scene files are provided, then the specified parallel
view defines the width, height, center, and orientation of the window
or facade of interest.
If one or more scene files are given, they
are presumed to contain planar surfaces over which
.I genklemsamp
will originate samples.
The sampled surface normals must correspond to the specified
view direction, and unaligned surfaces are silently ignored.
.PP
The
.I \-c
option specifies the number of rays to sample per Klems direction.
These samples will be distributed evenly over the surface(s).
The default setting is 1000.
.PP
The
.I \-ff
option specifies that output rays should be generated as 32-bit IEEE binary
float values.
This may be more efficient if passed directly to
.I rcontrib
or
.I rtrace(1)
with the same option.
Likewise, the
.I \-fd
option specifies 64-bit IEEE binary double values.
The default setting of
.I \-fa
produces ASCII floating point values.
.SH EXAMPLE
To generate 500 samples per direction over a set of south-facing windows and
pass to
.I rcontrib
to compute daylight coefficients in a matrix:
.IP "" .2i
genklemsamp -c 500 -vd 0 -1 0 -vu 0 0 1 south_windows.rad
| rcontrib -c 500 -e MF:1 -f reinhart.cal -b rbin -bn Nrbins exterior.oct > Dsouth.dat
.SH AUTHOR
Greg Ward
.SH "SEE ALSO"
dctimestep(1), genBSDF(1), genskyvec(1), mkillum(1),
rcontrib(1), rtrace(1), vwrays(1)
